SENSORY PLASTICITY

A prosthetic challenge is offered by the possibility of using the tactile sensory system to carry optical information from an artificial receptor to the brain. After a training period, sensory plasticity may enable such information to be perceived as three-dimensional “visual” information. Sensory plasticity is defined here as the ability of one sensory system (receptors, afferent pathways, and the central nervous system representation) to assume the functions of another system. Sensory information reaches the brain in the form of nerve impulses (Rushton 1961). There is no doubt that the temporal and spatial patterns of nerve impulses provide the basis of our sensory perception; the coding of information in the form of nerve impulse patterns is a fundamental concept in ncurophysiology and psychology (MeZzack & W a l l 1962). For example, visual information is sent along the optic nerves in the form of patterns of nerve action potentials. The optical images, per se, reach no farther than the retinal receptors. The brain must interpret the nerve impulses as a visual image, after decoding the patterns of afferent impulses. A large body of evidence indicates that the brain demonstrates both motor and sensory plasticity. The aim of this paper is to examine the evidence for plasticity as a fundamental basis for the development of a high resolution vision substitution system.